Digital still cameras are in wide use. Technologically sophisticated GUIs (graphical user interfaces) have come to be used in digital still cameras, and also, digital still cameras have come to be connected to a network. To meet such requirements for functionality enhancements, high-performance, high-functionality operating systems such as the Linux (registered trademark) have come to be executed in digital still cameras.
Activation of a high-performance, high-functionality, and large-scale operating system such as the Linux (registered trademark) generally takes a long time in comparison to activation of a small-scale operating system such as μITRON (micro industrial the real-time operating system nucleus).
Also, as processing in the application such as the GUI and network connection becomes sophisticated, the application program has become larger in scale, and its activation also takes increasingly more time.
This is also attributable to the fact that a NAND-type flash memory is used for storage of the operating system and the application program, instead of a NOR-type flash memory that allows a stored program to be executed directly. In a case where a program is stored in a NAND-type flash memory, to execute this program, it is necessary to load the program stored in the NAND-type flash memory into a RAM (random access memory) temporarily, and then execute the program loaded into the RAM.
Accordingly, in some conventional configurations, a non-volatile storage unit is arranged on a main storage, information necessary for continuing processing is saved into the non-volatile storage unit and power is shut off, and upon turning the power on, the processing interrupted by the power shutoff is resumed by using the information retained in the non-volatile storage unit, and also, each piece of information necessary for resuming the processing is identified and assigned priority, information is stored into the non-volatile storage unit in order of decreasing priority, and information that cannot not be stored into the non-volatile storage unit is saved into a secondary storage, thereby performing suspend and resume processing efficiently (see, for example, Patent Document 1).    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-362426